JP3393145B2 - Lithium ion secondary battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lithium ion secondary battery in which a positive electrode and a negative electrode face each other with a separator holding an electrolytic solution interposed therebetween, and more specifically, to a positive electrode, a negative electrode (electrode) and a separator. The present invention relates to a battery structure that can take any form such as a thin type by improving the electrical connection of the above.

BACKGROUND ART There is a great demand for reducing the size and weight of portable electronic devices, and in order to realize them, it is essential to improve the performance of batteries. Therefore, in recent years, various batteries have been developed and improved in order to improve the battery performance. Improvements in characteristics expected of batteries include higher voltage, higher energy density, higher load resistance, arbitrary shape, and ensuring safety. Among them, the lithium-ion battery is a secondary battery that can achieve the highest voltage, the highest energy density, and the high load resistance of the existing batteries, and its improvement is being actively pursued even now.

This lithium-ion secondary battery has a positive electrode, a negative electrode, and an ion conductive layer sandwiched between both electrodes as its main constituent elements. In lithium-ion secondary batteries that are currently in practical use, active material powder such as lithium-cobalt composite oxide is mixed with electronic conductor powder and binder resin for the positive electrode, and the mixture is applied to an aluminum current collector. As the negative electrode, a plate-shaped negative electrode is used in which a carbon-based active material powder is mixed with a binder resin and applied to a copper current collector. In addition, a porous film such as polyethylene or polypropylene filled with a non-aqueous solvent containing lithium ions is used for the ion conductive layer.

For example, FIG. 5 is a schematic sectional view showing the structure of a conventional cylindrical lithium ion secondary battery disclosed in Japanese Patent Laid-Open No. 8-83608. In the figure, 1 is an outer can made of stainless steel or the like that also serves as a negative electrode terminal, 2 is an electrode body housed in the outer can 1, and the electrode body 2 is formed by spirally winding a positive electrode 3, a separator 4 and a negative electrode 5. It is structured. In order to maintain the electrical connection of the positive electrode 3, the separator 4 and the negative electrode 5, this electrode body 2 needs to apply an external pressure between the electrodes. Therefore, the in-plane contact is maintained by putting the electrode body 2 in a strong metal can. In the case of a prismatic battery, a method is used in which strip-shaped electrode bodies are bundled and placed in a prismatic metal can to press down by applying force from the outside.

As described above, in the current commercially available lithium ion secondary batteries, a method of using a strong outer can made of metal or the like is used as a method of bringing the positive electrode and the negative electrode into close contact with each other. Without the outer can, the electrode surface is peeled off, and it becomes difficult to maintain the electrical connection between the electrodes via the ion conductive layer (separator), which deteriorates the battery characteristics. On the other hand, not only does this outer can reduce the energy density of the battery due to its large weight and volume in the battery, but the outer can itself is rigid, which limits the shape of the battery. Difficult to do.

Against this background, development of lithium-ion secondary batteries that do not require an outer can is being pursued with the aim of reducing weight and thickness. The point of development of a battery that does not require an outer can is how to maintain the electrical connection between the positive electrode and the negative electrode and the ion conductive layer (separator) sandwiched between them without applying external force. As one of the joining means that does not require such external force, a method of adhering the electrode and the separator using resin or the like has been proposed.

For example, Japanese Patent Application Laid-Open No. 5-159802 discloses a manufacturing method in which an ion conductive solid electrolyte layer, a positive electrode and a negative electrode are integrated by heating with a thermoplastic resin binder. In this case, since the electrodes and the electrolyte layer are integrated to bring the electrodes into close contact with each other, the electrical connection between the electrodes is maintained and the battery operates even without applying external force.

The conventional lithium-ion secondary battery is configured as described above, and in the case where a strong outer can is used to secure the adhesion between the electrode and the separator and the electrical connection between the electrodes, except for the power generation part. There is a problem in that the volume and weight of a certain outer can occupy the entire battery is large, which is disadvantageous in producing a battery having a high energy density. Also,
Although a method of adhering the electrode and the ionic conductor via the adhesive resin has been considered, for example, when the solid electrolyte and the electrode are simply adhered via the adhesive resin, the resistance of the adhesive resin layer is large. There is a problem that the ionic conduction resistance inside the battery cell is increased and the battery characteristics are deteriorated.

Furthermore, in the example of Japanese Patent Laid-Open No. 5159802, the electrode and the solid electrolyte are joined with a binder, but since the interface between the electrode and the electrolyte is covered with the binder, for example, compared with the case where a liquid electrolyte is used, ionic It is disadvantageous in terms of conductivity. for example,
Even if a binder having ionic conductivity is used, a material having ionic conductivity equal to or higher than that of the liquid electrolyte has not been generally found, and the same battery performance as a battery using the liquid electrolyte should be obtained. Had problems such as difficulty.

That is, in order to hold the liquid electrolyte at the interface between the electrode and the electrolyte, a metal outer can is necessary, which is disadvantageous in terms of energy density, while in the case of the electrode-electrolyte adhesive type, a metal outer can is required. Instead, compared to a battery using a liquid electrolyte, the conductivity between the electrode and the electrolyte is low, which is disadvantageous in terms of battery performance such as high load factor charge / discharge characteristics.

By the way, a non-aqueous electrolyte generally used in a lithium-ion battery has a conductivity of 1/10 or less as compared with an aqueous electrolyte. Therefore, it is necessary to increase the battery area and reduce the battery internal resistance. In order to make a large area electrode into a battery compactly, it is possible to make several strips and stack them,
There is a configuration in which an electrode is wound between strip-shaped separators, a configuration in which it is folded, and the like, but as a practical method of assembling a battery, it is general to construct a battery body by winding a strip-shaped separator and a strip-shaped electrode. It is possible to apply this configuration to the assembly of a battery in which the electrode and the separator are joined by an adhesive layer, but the method of winding while adhering is slower in writing speed than winding without adhering all. However, there was a problem that the assembly productivity was poor. Also,
If the tape band is used to fix the wound battery body from the outside without adhering it at all, the interface between the electrode and the separator does not adhere sufficiently, resulting in a large internal resistance, which is a practical problem especially in applications requiring a large current. there were.

The present invention, in order to solve such a problem, the present inventors have been made as a result of diligent studies on a preferred method of stacking the separator and the electrode, the adhesion between the electrode and the separator without using a strong outer can Therefore, it is an object of the present invention to obtain a practical lithium-ion secondary battery having low internal resistance with high productivity.

DISCLOSURE OF THE INVENTION A first lithium ion secondary battery according to the present invention is a strip-shaped positive electrode having a positive electrode active material layer and a positive electrode current collector, a strip negative electrode having a negative electrode active material layer and a negative electrode current collector, and lithium ion. A strip-shaped separator for holding an electrolyte containing
The positive electrode and the negative electrode are alternately arranged between the separators,
It is provided with a wound type laminated structure battery body in which only one of the positive electrode and the negative electrode and the separator are adhered by a porous adhesive resin layer holding the electrolyte. According to this, it is possible to fabricate a wound-type laminated structure battery body by winding a separator to one of the positive electrode and the negative electrode in advance together with the remaining negative electrode or the positive electrode, and comparing with the case of bonding at the same time as winding. The time required to dry the adhesive is reduced. Also, compared to the case where the positive electrode, the negative electrode, and the separator are wound without bonding at all, the electrode with the separator and the remaining electrode can be wound, so the operation is simple, and there is little deviation between the electrode and the separator, and the positive electrode and the negative electrode are in contact with each other. As a result, the probability of an internal short circuit occurring is low, and safety is improved. Further, since the adhesion between the electrode and the separator is high, a lithium ion secondary battery having a small battery internal resistance can be obtained.

Furthermore, the electrode and the separator can be brought into close contact with each other by the adhesive resin layer, and moreover, the electrolyte is retained in the through hole of the adhesive resin layer that communicates between the electrode and the separator, so that a good electrode-electrolyte interface is obtained. Since the ion conductivity can be secured, it is possible to obtain a lithium ion secondary battery which can be made higher in energy density and can be made thinner, and can have any form, and which is excellent in charge and discharge characteristics.

A second lithium-ion secondary battery according to the present invention is the above-mentioned first lithium-ion secondary battery, in which a fluororesin or a mixture containing a fluororesin as a main component is used as the adhesive resin layer.

A third lithium ion secondary battery according to the present invention is the above second lithium ion secondary battery, wherein polyvinylidene fluoride is used as the fluorine-based resin.

A fourth lithium ion secondary battery according to the present invention is the above first lithium ion secondary battery, wherein polyvinyl alcohol or a mixture containing polyvinyl alcohol as a main component is used as the adhesive resin layer. By using a fluorine-based resin or a mixture containing a fluorine-based resin as a main component, polyvinyl alcohol or a mixture containing polyvinyl alcohol as a main component as the adhesive resin layer,
The lithium ion secondary battery having the above-mentioned excellent characteristics can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing the structure of a plate-shaped wound type laminated structure electrode body of a lithium ion secondary battery according to an embodiment of the present invention, and FIG. It is a cross-sectional schematic diagram which shows the principal part of the electrode body shown in the figure, FIG. 3 is a characteristic diagram which shows the discharge characteristic of the battery of Examples 1-3 and the battery of a comparative example, and FIG. FIG. 5 is a characteristic diagram showing the relationship between the amount of the adhesive resin in the adhesive resin solution and the internal resistance when the adhesive resin layer according to the embodiment of the invention is formed. FIG. It is a cross-sectional schematic diagram which shows an example of the following battery.

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 is a schematic cross-sectional view showing the configuration of a flat-plate wound-type laminated structure electrode body for a lithium ion secondary battery according to an embodiment of the present invention, and FIG. FIG. 3 is a schematic cross-sectional view showing the structure of an enlarged main part of FIG. 1. The lithium-ion secondary battery according to the present invention is a flat plate-shaped laminate in which band-shaped positive electrodes and negative electrodes are alternately arranged between rolled-up band-shaped separators, and one of the positive and negative electrodes and the separator are bonded by an adhesive layer. It has a structure. In the figure, 3 is a positive electrode formed by joining a positive electrode active material layer 7 to a positive electrode current collector 6, 5 is a negative electrode formed by joining a negative electrode active material layer 9 to a negative electrode current collector 10, 4 is a positive electrode 3 and a negative electrode 5 A separator that is arranged between the separators and holds an electrolytic solution containing lithium ions, 11 is a porous adhesive resin layer 11 that joins the negative electrode active material layer 9 and the separator 4,
The adhesive resin layer 11 has a large number of through holes 12 that connect the negative electrode active material layer 9 and the separator 4, and the electrolytic solution is held in these through holes.

A strip-shaped positive electrode 3 and a negative electrode 4 are alternately arranged between the rolled-up strip-shaped separators 4, and one of the positive electrodes 3 and the negative electrodes 5 and the separator 4 are adhered with an adhesive layer 11 to form a flat-plate winding type laminated structure. Therefore, the positive electrode 3 and the negative electrode 5 are previously prepared.
A plate-shaped winding type laminated structure battery body can be produced by winding the one having the separator 4 adhered to either one of them together with the remaining negative electrode 5 or the positive electrode 3, and the adhesive of The time required for drying is shortened. Further, as compared with the case of winding the positive electrode, the negative electrode, and the separator without adhering at all, it is only necessary to wind the electrode with the separator and the remaining electrode, so that the workability is good and the winding device can be greatly simplified. Moreover, the deviation between the electrode and the separator is small, and the probability that the positive electrode and the negative electrode contact each other to cause an internal short circuit is low, and the safety is improved. Further, since the adhesion between the electrode and the separator is high, a lithium ion secondary battery having a small battery internal resistance can be obtained.

Furthermore, since the electrode layer (that is, the active material layer 7 or 9) and the separator 4 serving as the electrolyte layer are joined by the porous adhesive resin layer 11, the adhesion strength between the electrode and the separator can be secured. Further, the inside, that is, by holding the electrolytic solution in the through hole 12 communicating to the interface between the electrode and the separator formed in the adhesive resin layer 11, it is possible to ensure good ion conductivity of the electrode-electrolyte interface, It is possible to simultaneously reduce the ionic conduction resistance between the electrodes. It is possible to make the amount of ions coming in and out of the active material inside the electrodes and the moving speed and moving amount of the ions to the opposite electrode to the extent of a lithium ion battery having a conventional housing.

Further, for example, by bonding the end of the separator, which is the outermost layer at the end of winding, to the wound electrode body, the electrical connection between the electrodes can be maintained without applying external force. Therefore,
There is no need for a strong outer can to maintain the battery structure,
The battery can be made lighter and thinner, and the battery can take any form, and can have the same excellent charge / discharge characteristics and battery performance as a battery using an electrolytic solution.

Further, by setting the ion conductivity resistivity of the adhesive resin layer 11 holding the electrolytic solution to be equal to or less than the ion conductivity resistivity of the separator 4 holding the electrolytic solution, the adhesive resin layer 11
As a result, the charge / discharge characteristics of the battery can be maintained at the conventional battery level without degrading the charge / discharge characteristics.

The ionic conduction resistivity of the adhesive resin layer 11 can be adjusted mainly by changing its porosity and thickness. The porosity can be adjusted by, for example, the amount of the adhesive resin with respect to N-methylpyrrolidone in the adhesive resin solution forming the adhesive resin layer. The porosity is preferably equal to or higher than the porosity of the separator 4 used.

As the adhesive resin used for joining the active material layer and the separator, a resin that does not dissolve in the electrolytic solution and becomes a porous film without causing an electrochemical reaction inside the battery, for example, a fluororesin or a fluororesin is used. A mixture containing a main component, polyvinyl alcohol, or a mixture containing polyvinyl alcohol as a main component is used. Specifically, a polymer or copolymer having a fluorine atom in the molecular structure such as vinylidene fluoride or 4-fluoroethylene, a polymer or copolymer having a vinyl alcohol in the molecular skeleton, or polymethyl methacrylate. , Polystyrene, polyethylene,
A mixture with polypropylene, polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, polyethylene oxide and the like can be used. In particular, polyvinylidene fluoride, which is a fluororesin, is suitable.

The lithium ion secondary battery configured as described above,
An adhesive agent is applied to one surface of two strip-shaped separators 4, and a strip-shaped positive electrode 3 (or negative electrode) is sandwiched between the adhesive-coated surfaces of the separator 4 and attached, and the remaining negative electrode 5 (or positive electrode).
Is wound up in an oval shape so that the positive electrodes 3 and the negative electrodes 5 are alternately arranged between the separators 4.

As the active material used in the present invention, in the positive electrode, for example, a compound oxide of lithium and a transition metal such as cobalt, nickel or manganese, a chalcogen compound, or a compound compound of these or various addition elements Is used in the negative electrode, graphitizable carbon, non-graphitizable carbon, polyacenes, carbonaceous compounds such as polyacetylene,
Aromatic hydrocarbon compounds containing an acene structure, such as pyrene and perylene, are preferably used, but any substance that can store and release lithium ions, which is the main component of battery operation, can be used. Further, these active materials are used in the form of particles, and the particle size can be 0.3 to 20 μm, and particularly preferably 0.3 to 5 μm.

As the binder resin used for forming the active material into an electrode plate, any binder resin that does not dissolve in the electrolytic solution and does not cause an electrochemical reaction inside the electrode laminate can be used. Specifically, vinylidene fluoride, ethylene fluoride, acrylonitrile, a homopolymer or copolymer of ethylene oxide, ethylene propylene diamine rubber and the like can be used.

Further, as the current collector, any metal that is stable in the battery can be used, but aluminum is preferably used for the positive electrode and copper is preferably used for the negative electrode. The shape of the current collector may be foil, mesh, expanded metal or the like, but mesh, expanded metal or the like having a large void area is preferable from the viewpoint of facilitating retention of the electrolytic solution after bonding.

In addition, the adhesive resin used for bonding the current collector and the electrode, like the adhesive resin used for bonding the electrode and the separator, does not dissolve in the electrolytic solution, does not cause an electrochemical reaction inside the battery, and is porous. A film is used. Specifically, a polymer having a fluorine molecule in its molecular structure such as vinylidene fluoride or 4-fluoroethylene, a mixture with polymethylmethacrylate, polystyrene, polyethylene, polypropylene, or the like, or a heavy chain having vinyl alcohol in its molecular skeleton. Polymers or copolymers, or mixtures of polymethylmethacrylate, polystyrene, polyethylene, polypropylene, polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, polyethylene oxide and the like can be used. Particularly, polyvinylidene fluoride or polyvinyl alcohol is suitable.

Further, as the separator, any one having sufficient strength such as an electronically insulating porous film, a net and a non-woven fabric can be used. The material is not particularly limited, but polyethylene and polypropylene are preferable from the viewpoint of adhesiveness and safety.

Further, as a solvent and an electrolyte salt provided for an electrolytic solution used as an ion conductor, a non-aqueous solvent and an electrolyte salt containing lithium which are used in conventional batteries can be used. Specifically, ether-based solvents such as dimethoxyethane, diethoxyethane, diethyl ether and dimethyl ether, single solutions of ester-based solvents such as propylene carbonate, ethylene carbonate, diethyl carbonate and dimethyl carbonate, and the same solvent or different solvents described above. It is possible to use a mixed solution of two kinds of The electrolyte salt used in the electrolytic solution is LiPF ₆ , LiAsF ₆ , LiClO ₄ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (C
_{F 3 SO 2) 2, LiN} (C 2 F 5 SO 2) 2, LiC (CF 3 SO 2) 3 , or the like can be used.

As a means for applying the adhesive resin, a method using a bar coater, a method using a spray gun, or a dipping method is used.

Hereinafter, the present invention will be described with reference to examples, but of course the present invention is not limited thereto.

Example 1 (Preparation of Positive Electrode) A positive electrode active material paste prepared by dispersing 87 parts by weight of LiCoO ₂ , 8 parts by weight of graphite powder, and 5 parts by weight of polyvinylidene fluoride in N-methylpyrrolidone was used as a positive electrode collector. An active material thin film was formed on a 20-μm-thick strip-shaped aluminum foil, which is an electric body, by applying a doctor blade method while adjusting the thickness to 150 μm. This is left to dry in a dryer at 60 ° C for 60 minutes, and then the thickness of the positive electrode active material layer is 100 μm.
By pressing so that the positive electrode active material layer 7 having a thickness of 100 μm was formed on the aluminum foil positive electrode current collector 6, a strip-shaped positive electrode 3 was produced.

(Preparation of Negative Electrode) Negative electrode active material paste prepared by dispersing 95 parts by weight of mesophase microbead carbon (trade name: manufactured by Osaka Gas) and 5 parts by weight of polyvinylidene fluoride in N-methylpyrrolidone (abbreviated as NMP). The thickness of the negative electrode current collector
Thickness of 20 μm strip-shaped copper foil by doctor blade method
The active material thin film was formed by coating while adjusting the thickness to 150 μm.
This is left to dry in a dryer at 60 ° C for 60 minutes, and then pressed so that the thickness of the negative electrode active material layer is 100 µm, so that 100 µm of the negative electrode active material is placed on the copper foil negative electrode current collector 10. A strip-shaped negative electrode 5 on which the layer 9 was formed was produced.

(Adjustment of Adhesive Resin Solution) First, 5 parts by weight of polyvinylidene fluoride and 5 parts by weight of finely powdered alumina (Aerosil C manufactured by Aerosil) as a filler are dissolved in N-methylpyrrolidone (hereinafter abbreviated as NMP) by suspension suspension, A viscous adhesive resin solution was prepared by sufficiently stirring so as to obtain a uniform solution.

(Preparation of Battery) The adhesive resin solution prepared as described above is uniformly applied to one surface of each of the strip-shaped polyethylene porous sheets (ME9630 manufactured by Asahi Kasei) that will be the two separators 4, and then the adhesive is dried. The strip-shaped negative electrode 5 (or positive electrode) prepared above is sandwiched between the coated surfaces of the separator to be in close contact with each other, and are bonded together. At this time, the width and length of the separator 4 are made slightly larger than the negative electrode 5 (or the positive electrode). Next, the negative electrode 5 (or the positive electrode) to which the separator 4 was attached was put in a warm air dryer at about 80 ° C. to evaporate NMP. At this time, after the NMP is removed, it becomes the through hole 12 in the adhesive layer 11.

Next, the strip-shaped positive electrode 3 (or the negative electrode) is replaced with the strip-shaped negative electrode 5
(Or the positive electrode) is arranged so as to protrude to one outside of one of the separators 4 attached to the (or positive electrode), and the positive electrode 3 (or the negative electrode) protruding to the outside surface of the other separator 4 is bent,
A separator with a negative electrode 5 (or positive electrode) is rolled up in an elliptical shape so as to wrap the folded positive electrode 3 (or negative electrode) inside, and the remaining separator portion at the end of winding is bonded and fixed to the rolled up electrode body with an adhesive. Then, a flat-plate winding type laminated structure electrode body was produced.

After depressurizing the plate-like laminated structure electrode body sufficiently dried to 50 Toor, dissolve lithium hexafluorophosphate at a concentration of 1.0 mol / dm ³ in a mixed solvent of ethylene carbonate and dimethyl carbonate (molar ratio 1: 1). After immersing in
A bag made of an aluminum laminate film was heat-sealed and sealed to obtain a lithium ion secondary battery having a flat laminated battery body.

Using the same electrode and separator as in the lithium-ion secondary battery according to Example 1 obtained as described above, the same electrolyte solution was applied to the electrode body wound up without any adhesion and fixed with a tape band from the outside. A battery according to a comparative example, which was injected and enclosed with an aluminum laminate film, and Example 1
FIG. 3 shows a comparison of the discharge characteristics with the battery according to. From the figure, it can be seen that Example 1 has a smaller internal resistance, and therefore the capacity capable of discharging even a larger current is maintained.

In the characteristic diagram of FIG. 4, the amount of the adhesive resin in the adhesive resin solution was changed to 5 parts by weight, 7 parts by weight, and 10 parts by weight with respect to NMP, with the filler being 5 parts by weight, and the adhesive resin layer was formed. It shows the internal resistance of the battery in the case. It can be seen that the resistance increases rapidly between 5 and 7 parts by weight.
Since the thickness of the adhesive resin layer 11 is proportional to the amount of the adhesive resin in the adhesive resin solution, the electrolytic solution retention rate and the distribution state of the electrolytic solution in the adhesive resin layer 11 are in this region. It is considered that the resistance sharply increased due to the rapid change. In addition, the resistance value at 5 parts by weight is as follows.
It was almost the same as the resistance value measured by applying a sufficient surface pressure between 5 and the separator 4.

Example 2 In the same manner as in Example 1 except that only the adhesive resin solution shown in Example 1 was changed, a battery having a flat plate-shaped laminated structure electrode body as shown in FIG. 1 was produced. .

(Preparation of adhesive resin solution) Polytetrafluoroethylene, copolymer of vinylidene fluoride and acrylonitrile, mixture of polyvinylidene fluoride and polyacrylonitrile, mixture of polyvinylidene fluoride and polyethylene oxide, mixture of polyvinylidene fluoride and polyethylene terephthalate, polyfluoride A mixture of vinylidene fluoride and poly (methyl methacrylate), a mixture of polyvinylidene fluoride and polystyrene, a mixture of polyvinylidene fluoride and polypropylene, and a mixture of polyvinylidene fluoride and polyethylene, each having the same composition ratio as N-
A viscous adhesive resin solution was prepared by mixing with methylpyrrolidone.

Using this adhesive resin solution, a battery having a flat-plate winding-type laminated structure electrode body was prepared in the same manner as in Example 1. The discharge current-capacity characteristics of this battery were superior to those of the comparative example, as shown in FIG.

Example 3 In the same manner as in Example 1 except that only the adhesive resin solution shown in Example 1 was changed, a battery having a flat plate-shaped laminated structure electrode body as shown in FIG. 1 was produced. .

(Adjustment of adhesive resin solution) Viscous adhesive solution by dissolving or mixing polyvinyl alcohol, a mixture of polyvinyl alcohol and polyvinylidene fluoride, a mixture of polyvinyl alcohol and polyacrylonitrile, and a mixture of polyvinyl alcohol and polyethylene oxide in NMP. Was produced.

Using these adhesive resin solutions, a battery having a flat-plate winding-type laminated structure battery body was obtained in the same manner as in Example 1 above. The discharge current-capacity characteristics of this battery were superior to those of the comparative example, as shown in FIG.

Although the adhesive resin solution is applied by the bar coater method in the above embodiment, the adhesive resin solution may be applied by a spray gun.

In the above-mentioned examples, the positive electrode 3 and the negative electrode 5 are shown as the case where the electrode having the active material layer bonded to the current collector is used. However, the electrode having the active material layer itself as the current collector may be used. Good.

Industrial Applicability It is used as a secondary battery for portable electronic devices such as mobile personal computers and mobile phones, and it is possible to improve the performance of the battery and make it smaller, lighter, and arbitrarily shaped.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Aragane 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Hiroaki Urushiba 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (72) Inventor Koji Hamano 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Ikuhiro Yoshida 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (( 72) Inventor Takayuki Inuzuka 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Michio Murai 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (56) References Patent flat 10-275630 (JP, a) JP flat 10-275629 (JP, a) WO 97/8763 (WO, A1) (58 ) investigated the field (Int.Cl. ⁷ DB name) H01M 10/40 H01M 4/02 - 4/04 H01M 2/16 H01M 6/16

Claims (4)

(57) [Claims] 1. A belt-shaped positive electrode having a positive electrode active material layer and a positive electrode current collector, a belt-shaped negative electrode having a negative electrode active material layer and a negative electrode current collector,
And a strip-shaped separator holding an electrolyte containing lithium ions, the positive electrode and the negative electrode are alternately arranged between the separator, only one of the positive electrode and the negative electrode and the separator is porous to hold the electrolyte. 2. A lithium-ion secondary battery comprising a wound-type laminated structure battery body adhered by the adhesive resin layer of 1. 2. The lithium ion secondary battery according to claim 1, wherein a fluorine resin or a mixture containing a fluorine resin as a main component is used as the adhesive resin layer. 3. The lithium ion secondary battery according to claim 2, wherein polyvinylidene fluoride is used as the fluorine-based resin. 4. The lithium ion secondary battery according to claim 1, wherein polyvinyl alcohol or a mixture containing polyvinyl alcohol as a main component is used as the adhesive resin layer.